1. Field of the Invention
The present invention is directed to an improved process for making alkaline earth metal borated sulfonates.
Preventing and/or reducing wear, as well as improving friction properties, are very important properties of lubricating oil compositions. Boron-containing additives, especially alkaline earth metal borated sulfonates, have been found not only to have excellent anti-friction properties when employed in lubricating oil compositions but also to provide detergent, anti-rust, anti-corrosion, and extreme pressure properties.
The present invention is directed to the discovery of an improved method of making alkaline earth metal borated sulfonates.
2. Background Art
Inoue et al., U.S. Pat. No. 4,683,126, discloses a method for producing an alkaline earth metal borate dispersion comprising two steps. The first step comprises reacting at 20°-100° C. a mixture of the following ingredients (A) to (E): (A) 100 parts by weight of the oil-soluble neutral sulfonate of an alkaline earth metal, (B) 10-100 parts by weight of the hydroxide or oxide of an alkaline earth metal, (C) boric acid in an amount which is 0.5-6.5 times in mol that of the ingredient (B), (D) 5-50 parts by weight of water, and (E) 50-200 parts by weight of a dilution solvent. The second step comprises heating the resulting reaction mixture of the first step to 100°-200° C. to remove the water and a part of the dilution solvent as required.
Hellmuth et al., U.S. Pat. No. 3,480,548 discloses a lubricating oil composition prepared by reacting a lubricating oil dispersion of an alkaline earth metal carbonate and alkaline earth metal hydrocarbon sulfonate with a boron compound selected from the group consisting of boric acids, boron oxides, and aqueous alkyl esters of boric acids.
Hellmuth et al., U.S. Pat. No. 3,679,584 discloses a process for increasing the alkaline earth metal ratio of an alkaline earth metal carbonate overbased alkaline earth metal sulfonate lubricating oil composition comprising introduction into a lubricating oil medium containing a colloidal-like dispersion of an alkaline earth metal carbonate overbased alkaline earth metal sulfonate, an alkaline earth metal hydroxide and boric acid and subsequently contacting the resultant mixture with carbon dioxide.
Fischer et al., U.S. Pat. No. 4,744,920 discloses a carbonated overbased product that has been borated. Specifically, the process comprises (a) mixing an overbased sulfonate and any required inert liquid medium, (b) borating the mixture (a) with a borating agent at a temperature less than at which substantial foaming occurs, (c) raising the temperature of the mixture (b) to that temperature in excess of the boiling point of water within the mixture (b), (d) separating substantially all of the water from the reaction mixture (c) while retaining substantially all of the carbonate in the mixture (c) and, (e) recovering the product (d) as high carbonate content borated product.
Schlicht, U.S. Pat. No. 4,965,003 discloses a process for preparing a borated, overbased oil-soluble metal detergent additive for lubricants, said process comprising (a) mixing a metal salt dissolved in a hydrocarbon solvent with a metal base and a polar solvent; (b) treating said metal salt mixture at a temperature ranging from about 10° C. to about 100° C. while passing an acid gas through the mixture; (c) filtering said treated mixture at a temperature of about 10° C. to about 100° C.; (d) adding a borating agent to said filtrate and reacting said filtrate for a period of about 0.25 to about 5.0 hours at a temperature ranging from about 15° C. to about 100° C.; (e) heating said borated mixture at a temperature sufficiently high to distill a major portion of the polar solvent and water therefrom; (f cooling the distilled borated mixture to below the boiling point of the remaining solvent and filtering said cooled filtrate mixture; and (g) stripping the cooled distilled filtrate mixture under a pressure ranging from about 10 to about 200 mm Hg at a temperature ranging from about 20° C. to about 150° C., thereby recovering the borated metal detergent additive.
Schlicht et al., U.S. Pat. No. 4,965,004 discloses (a) adding a borating agent to an overbased metal salt in the presence of a protic solvent and a hydrocarbon solvent and reacting for a period of about 0.25 to about 5.0 hours at a temperature ranging from about 15° C. to about 100° C.; (b) heating said borated metal salt mixture at a temperature sufficiently high to distill an amount of distillate equal to at least about 80 percent of the protic solvent fed; (c) cooling the distilled borated mixture to below the boiling point of the remaining solvent and filtering said cooled filtrate mixture; and (d) stripping the cooled distilled filtrate mixture under a pressure ranging from about 10 to about 200 mm Hg at a temperature ranging from about 20° C. to about 150° C., and recovering the borated metal detergent additive.